Next we will talk about the size and weight of solar panels, these two characteristics of the panels are important when choosing the most suitable modules for you.

When designing a photovoltaic installation we must take into account not only its power. The dimensions and weight of the solar panels we use are also important, especially if it is photovoltaic on the roofs of buildings. What are their sizes and how much do photovoltaic panels weigh?

## What are the dimensions of the photovoltaic panels?

First, let’s take a look at the dimensions achieved by photovoltaic panels. **The dimensions depend, among other things, on the number of links. ** We distinguish 48, 60 and 72 cell photovoltaic panels, of which the 60 cell version is the most popular in domestic installations. They have good mechanical properties and are easy to install.

The dimensions of the photovoltaic panels themselves have been standardized over the years. For example, a 280W polycrystalline panel is approximately 100cm wide and up to 170cm long. Its thickness is 4 cm.

**Standard photovoltaic panel – dimensions** (average for 60 cell polycrystalline panels):

- length: 165-170 cm,
- width: 100-102 cm,
- thickness: 4 cm.

## The size of solar panels: what does it depend on?

**The size of photovoltaic panels mainly depends on the number of cells used** , which we briefly mentioned above: 40, 60 or 72 cells per panel (average cell dimensions are 15 × 15 cm). However, this does not have a significant impact on the difference in the scale of the investments, since their efficiency is more important.

Of course, 72-cell panels are larger and heavier than 60-cell products, for example:

- SPR-MAX3-400 model with 60 cells (dimensions: 1690 × 1046 mm, weight: 19 kg);
- 72-cell BEM 360Wp Prestige Power model (dimensions: 1960 × 992 mm, weight: 21.3 kg).

**More important than the dimensions of the photovoltaic panels is their efficiency** , that is, the amount of light converted into electricity. The prices of photovoltaic panels are also increasing in proportion to the increase in efficiency. Therefore, we should find the optimum between its efficiency and cost. The power of the photovoltaic installation must cover the demand for electricity, on the other hand, the payback period must be as short as possible, including the calculations obtained from the photovoltaic subsidy.

The higher the power in a single module, the fewer panels we will need to achieve the desired power of the photovoltaic installation. As a result, the photovoltaic installation will take up less space, which is important especially for small roofs.

For example, for a 5 kWp installation, we need 15 panels with a capacity of 350 Wp or 17 panels that generate 300 Wp. If we assume that our installation must have a power of 3 kWp, it will be 8-9 (350 Wp) or 10 panels (300 Wp) respectively.

In this way, we can choose them optimally in relation to the surface of the roof of the building, taking into account its slope. We must also remember that on a roof with a slope of 30-35%, on average, 1 kilowatt of power (4 panels of 250 Wp) requires about 6.5 m2. on the surface, on a flat roof and on the ground, even up to 15 square meters. Such a big difference is due to the obligation to install special frames that allow the optimum angle of incidence of sunlight to be reached.

## How much do solar panels weigh?

Another important consideration when creating an installation is the weight generated by the photovoltaic panels. Weight is crucial for safety, especially if it is panels that are mounted on the roof of the house. **If we know how much the photovoltaic panel weighs, we can calculate if the bearing capacity of the roof is sufficient** or if it is necessary to install them on the ground.

A standard panel weighs 18 to 25 kg. Its weight increases with size (for example, the average weight of a 72-cell panel is about 22.5 kg).

Also, the construction of the photovoltaic panel is important for the weight. **The weight of a traditional panel covered with tempered glass on the top and a protective foil on the bottom is an average of 18-20 kg. ** The photovoltaic panels glass-glass are heavier and are protected on both sides by tempered glass. The double-glazed panels will be appreciated when cladding, among other shelters and terraces. However, if we are the owners of older buildings, in addition to the higher price, we must remember its greater weight, from 3 to 6 kg in one panel.

## Installation of photovoltaic panels: on the roof or on the ground?

If we average the weight of the panels in approximately 20 kg, the load capacity of the roof must be at least 250 kg / m2. For smaller structures and installations on the roof, the weight of the entire structure needs to be recalculated.

Therefore, for larger installations with a power greater than 10 kWp , solar panels are mounted only on the ground , where their weight does not play such an important role. In addition, support structures are suitable for installations where mounting possibilities are limited by the roof structure (eg chimneys, roof windows).

They ensure the optimum angle of incidence of sunlight and guarantee the strength and rigidity of the panels. In addition, they are structures made of aluminum, which prevent the formation of corrosion cells (not to be confused with steel structures).

Another alternative is the installation of panels in a garage or outbuilding, if of course we have such a place on our plot. We can also opt for facade systems or innovative photovoltaic tiles. However, due to the higher costs, only investors who build the house from scratch or do a general roof renovation decide on this solution.

In summary, the area and weight of a photovoltaic installation mainly depend on the efficiency of the photovoltaic panels used. With it, however, its price increases. Therefore, we must find the optimal solution between the cost of installation and the size and weight of the panels, with the help of specialists. Even if the structure or load-bearing capacity of the roof does not allow the installation of panels of adequate power, they will propose an alternative solution (for example, supporting structures, installation on the ground, panels in an agricultural building, etc.).